


Tiniest Genius

by HailSam



Category: Undertale (Video Game)
Genre: Gen, Happy together, I Made Myself Cry, Laboratories, Parent W. D. Gaster, Possibly Papyrus, Terminal Illnesses, just two old men, let them be happy, still gen
Language: English
Status: In-Progress
Published: 2020-01-15
Updated: 2020-05-22
Packaged: 2021-02-27 05:13:44
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 8,874
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22261630
Author URL: https://archiveofourown.org/users/HailSam/pseuds/HailSam
Summary: Sans is very young, and very smart. His daddy takes him to the lab, and he gets to help the adults be even better adults! Through math! Join Sans as he journeys his way through life as a genius child who has a...hard life ahead.
Relationships: Asgore Dreemurr/W. D. Gaster, Grillby/Sans (Undertale)
Comments: 59
Kudos: 121





	1. Gaster's Laboratory

**Author's Note:**

  * For [Theslowesthnery](https://archiveofourown.org/gifts?recipient=Theslowesthnery).



> You can find me:  
> https://twitter.com/sassyhaillive  
> https://www.pillowfort.social/HailSam  
> https://sassyhail.tumblr.com/
> 
> If you need on Pillowfort or even an invite here, let me know I'll help you out :)

**Summary for the Chapter:**

> Gaster brings his son to work under mysterious circumstances.

**Notes for the Chapter:**

> https://twitter.com/theslowesthnery/status/1217195541433589768
> 
> This is the tweet that started it all off so you can all cry with me.

“So he’s…the doc’s kid?”

The group of scientists stared from across the room where they had surrounded a table. They were a mix of humans and monsters, two human women and a man, an odd monster who seemed as thin as a rod while another had a bobbing funny flat head. The man had spoken up, his hair black as the slate of their chalkboard. His nametag said ‘Roswell’, and under it he drew a funny spaceship. He had sharp rectangular glasses that sat on the tip of his nose.

The flat headed monster, whose name was ‘Blobber’ surprisingly, nodded in the ragdoll way he had. “Yeah, Gaster said he went and pulverized all the online courses.”

“Yeesh.”

The doctor in question was at the markerboard of the room, magic hands scribbling away on it as he read over a clipboard. Next to him, barely knee-height, stood a little skeleton child in his own labcoat. The sleeves were too long and had to be rolled back, and he had big cute glasses on his face. Gaster had him dressed in a cute set of overalls under the lab coat. The only difference between a visiting child and him was the fact that he’d erase a number and shakily scrawl out a new one, a high-pitched voice squeaking out an answer like, ‘Dat isn’t da numewical!’ or ‘You fowgot da hypot-a-nuse.’

In response, Gaster would nod along, or smile down at him and chatter to him before going back to whatever problem they were solving.

One of the women, her hair blonde and in a ponytail as she sipped some noodles, spoke up. “I think it’s adorable. He’s a Dad, that’s like. Hot, you know.” 

Roswell gave her a blank look. “Hot? Jill, really, hot?”

Jill shrugged, twirling a fork in her noodles. “Yeah, domesticity elicits warm cozy feelings in some of us, Rossy.” She stuck her tongue out, swallowing down her food before taking a drink. 

Blobber nodded again. “It is rather…nice to see him like this, I suppose. Still. You don’t think that’s like, his clone instead of his son though?”

The other woman, half purple and half green hair in braids, scoffed. “I doubt it. If the doc made his own clone, he wouldn’t shut up about it for months, I can feel it.”

The thin monster laughed nervously, adjusting his bowtie. “Y-Yes, I suppose, Cara, but did any of us know he had a child?”

They paused on that, watching the father-son duo for a moment. No. No, none of them really knew the doc’s life beyond the lab. Sure they all sometimes went off to drink or relax, and invited him along, but he always declined. Jill made a noise. “Now we know what he’s got more important than bar hopping.”

Roswell nodded slowly, pushing his glasses up with the tip of his finger. “Guess so. You don’t think he’ll sign us up for babysittin’, do ya?”

The others shrugged, eventually returning to their interrupted lunch, every so often looking over at the small child who would argue about the nature of physics without a care in the world.

———————————

“Watch him for a moment,” Gaster passed by, hefting the child up into a chair near Roswell who was on his normal break. He sputtered, sitting up from where he had propped his feet up on the table.

“Wha-me-why!”

“I have an experiment about to go wrong, just for a second. Be good, Sans,” Gaster kissed Sans’ head and Sans giggled, adjusting his glasses.

“I will, Daddy!” Gaster nodded, shooting Roswell a look.

“I hope to come back to him just in the same condition I left him.” Well. If that wasn’t a threat, Roswell wasn’t sure what was. He gave a lazy salute as the doctor whirled around, stalking down the hallway with ease. Roswell sighed, then looked over at the shorter skeleton. He was so short, he could barely peek over the table, his chin on top of his hands as he peeked at the human with wide eyes.

“Soooo. You want some juice?”

“Yea!” Sans tapped his hands against the table and Roswell hefted himself out of the chair. He got an apple juice from the vending machine, sliding it to Sans who tugged on the straw on the back curiously. Roswell flopped back into the chair, staring at him.

“Sooo. Just you and the doc huh?”

“Yuh-huh, me and Daddy,” Sans mumbled, his slightly stumpy fingers fumbling with the paper around the straw.

Roswell nodded. “Huh. Cool. You um, go to school?” A shake of the head. “…oh. You gonna…be here now I guess?” A shrug. Well. Enlightening conversation. Sans started pulling at the paper, tapping the straw fiercely against the table. “So have you ever gone to school? Wait how are skeletons made anyway?” he muttered to himself, overlooking Sans’ frantic attempts to open the juice.

He nearly had it if not for Jill appearing behind him, startling him. “Hey, what’s-oh shit!” 

Sans squished the box of juice tightly in his hands, erupting the yellow liquid despite not having a straw inside. It spilled over his nice overalls, part of his lab coat, and onto the seat. Roswell stared, Jill had her hands over her mouth, and Sans…

…started to tear up, his breath hitching as he threw the box and nearly hit Roswell had he not dodged. His head hit the table and he cried, his shoulders shaking and Jill made an ‘aww’ noise. She kneeled down, gently rubbing his back as the poor kid sobbed his soul out. “Oh honey it’s okay, hey, juice is hard,” she comforted him, glaring at Roswell who gave a sheepish grin with a shrug.

Sans sniffled, scrubbing at his face with a juice-soaked sleeve. “B-But Mistah gave it t’meeee,” he whined out and Jill sighed.

“Then we’ll get another. We gotta clean you up before it gets all sticky.” Sans nodded sadly, hiccuping every so often as Jill helped him out of the seat. She peeled the lab coat from him, tossing a roll of paper towels at Roswell’s head. “Clean up the table.”

“Heeey why’re you mad at me?”

Jill huffed, a hand on her hip. “He’s a kid! You should’ve opened it up for him!” Sans stood next to her, looking smaller than ever. Roswell snorted, rolling his eyes as he pulled free a paper towel.

“I don’t have kids! I don’t know this shit.”

“Well now you do. C’mon, kiddo. What’s your name?”

“S-S-Saaaans,” he mumbled, still crying as she lead him to the small bathrooms to the side. Roswell grumbled a bit, but he did feel bad for not seeing the kid struggling with opening it. He just hoped Gaster didn’t, you know, kill him, or throw him in lava…actually what DID the doctor do when mad?

He felt like it’d be a bad idea to find out.

The table was easy to clean, along with the seat and some of the floor. When Jill came back with Sans, he had a new lab coat on, but his face was flushed (skeletons could do that?) and he looked downtrodden. Jill patted his shoulder softly. “I told Sans we could see the centrifuge and spin some dolls around in it.”

You can take the kid to a lab, but you can’t take the kid out of him. Roswell snorted. “Boring, let’s put some of Cara’s experiments in it and see if it explodes.”

Sans gasped and clapped, bouncing in place. “Boom boom!”

A huge regret, on both their parts, as Cara’s experiment ate through the centrifuge and they got a stern dressing down from Gaster (for endangering his son, ruining Cara’s experiment, and for not using a dummy like they were meant to), but Sans seemed pleased and happy, the incident from earlier having been forgotten.

Honestly, they both thought they got away with it, were it not for Gaster asking why Sans was in a different lab coat than the play one he had on earlier.

Whoops.

—————————

“It gotta be a twee.”

Tonk, the tall thin monster, paused in his scribblings on the chalkboard. He blinked, looking over at the tiny child that was visiting that day. He laughed nervously. “H-Hm? What?”

The skeleton pointed at the top number, a five Tonk had wrote in. “Twee!”

Tonk blinked, slowly adjusting the number to a three…and then it started to flow better, the numbers no longer being cranked out slowly but flowing like a waterfall. He laughed, tapping the chalk against the board. “Good job! You’re brilliant! I wouldn’t have noticed for a very long time!”

The boy blinked, then brought up a special sippy cup for the in between ages of not yet able to hold a cup, but beyond the time for a bottle. “Thankee. Do you know wheres Daddy went?”

“Let’s go find him!” Tonk put the chalk down, brushing off his hands before offering his hand hesitantly. The skeleton took it easily, still draining the cup of whatever juice he had for the day.

In Gaster’s office, Cara and he were looking at something through a high powered microscope, Gaster scribbling down on a clipboard. Cara cleared her throat. “So.”

“..so…?”

“The kid, Doc, the kid.”

Gaster made a noise, a click sounding as he enhanced the magnification. “Yes, my son, Sans. Brilliant boy, isn’t he?”

Cara scoffed, lifting her eyes from her own microscope. “That’s not my question.”

“You didn’t ask one.”

Okay, he had her there. She sighed, standing up straighter as she leaned against the table. “What prompted this on? The bringing your kid to work day?” No answer, not for a while, just the steady scribbling of Gaster’s magic on a clipboard. “C’mon. We’re your team, you can tell us.”

Still no answer, and at first she thought she wouldn’t get one, until he sighed softly, leaning up but still staring at the microscope. “The doctors say he’s sick.”

Cara frowned, her mind flicking over what ‘sick’ could mean before pumping the brakes. Monsters. Right. Different. “…what do you mean?”

“Infant monsters start off at 5 HP. If you recall, Blobber once stated how a cousin of his oddly had 17 HP at age 8.”

Cara nodded. She didn’t know how HP played into things very well, but she knew like in a game, it was important to the well-being of the monsters. “Right, yeah, I remember.”

Gaster stared ahead for a moment. “Sans only has 1 HP. He had 5, at first…then last year he went down to 3…I took him last week to the doctor’s.” His hand started tapping a rhythm on the table. “His steady dropping is concerning.” He let out a slightly shaky breath. “…I’m spending time with my child.”

Cara reached over, and covered his hand, squeezing tightly for a moment. “I’m sorry.”

They sat in silence for a moment before the door opened, Tonk holding the hand of said little boy. “Hello sir-…ah…did we interrupt?” he mumbled, looking at Cara in worry before Sans hurried over, giggling as he held onto Gaster’s pant leg.

“Daddy! Tonk puts a five instead of a twee!” He squeaked, and Gaster smiled down at him, leaning down and picking him up.

“And you helped him, hm, smart boy?”

Sans grinned brightly, as bright as the sun, Cara imagined, if the sun came down to Earth to bless them with its warmth.

**Notes for the Chapter:**

> Why can't I make a happy story without such a dark foreboding secret under it
> 
> This is all Hnery's fault but like also mine
> 
> Take this


	2. Sans...

**Summary for the Chapter:**

> The worst has happened, and Gaster isn't taking things well.

**Notes for the Chapter:**

> Not THE worst, but Gaster's not gonna think too hard on that part.

They never did experiments on monsters or humans. Ever. Not even when the end result would have garnered them more data than the test dummies would.

But this was no experiment. This was saving a child’s life. Their boss’ son’s life.

It wasn’t that they came up with it out of nowhere. Gaster had taken a day off to take Sans to the doctor’s. Cara seemed nervous, and Tonk wished them a good trip. They didn’t hear anything that day of what happened, not that any of them expected it. Their boss was a reserved man about his private life, which was why it was odd when he brought his son to work.

The next day was…bad.

Sans seemed enthusiastic as always, a sippy cup in hand, a striped sweater on underneath his labcoat, taking Blobber’s hand in his and pointing out the errors in the mathematical equation for the new serum for some experiment or another. Gaster looked like someone sucked the pallor from his face, and he sat down heavily at the table. Cara hesitantly reached over and patted his shoulder. “…bad…?”

Gaster let out a slow breath, balancing his elbows on the table and crossing his fingers together. “Yes. In a manner.”

Roswell frowned, looking over at where the kid was waving his sippy cup and back at Gaster. “What’d they say?”

“Sans hasn’t gone down yet, he remains at 3 HP…however his MAGIC stats are increasing with his age, as they should.” Gaster mumbled, a long finger tapping against his other hand. “They’re worried with the increase, and the fact that his magic will build over time along with keeping his body stable, that it will make him bedridden for a while, or all his life.” He let out a sigh. “For now, he’s stable. But any dangerous increase, and…”

Cara nodded. “There’s nothing they can do?”

“No,” Gaster looked away, letting out a huff. “It feels like I’m waiting for a bomb to go off…” Jill frowned from where she was cradling a mug of tea.

“They can’t see when it’ll happen, or some sort of warning signs?”

“No no, nothing like this has ever happened,” Gaster shook his head. “I don’t even know if…” he trailed off, leaving the words to dangle around them. Roswell grunted. 

“Well, we’re pretty awesome at finding things that have never happened. We should-”

“I’m not using my child,” Gaster snarled, “as a lab rat.”

Gaster would not have the option to say no, however.

The doctors would say that it was out of their hands…they had said that many, many times…which is why when what happened, happened, Gaster brought Sans to the lab instead. They outfitted a room much like a hospital room, a large white bed with a small skeleton in it, seemingly asleep.

If only. 

He was in a coma, or something like a human coma. His magick was sluggish, soul beating very slowly. Gaster seemed just as concentrated as ever, intent on curing his son (but Cara had seen him, one late night, slouched in a chair, head in his hands as he sat there, looking for all the world a man defeated.)

Nothing changed, however. Steady at 1 HP, Sans slept on. A hand would twitch, or he would shift in his sleep, or sigh, but other than that, there was no waking him up. For now, at least.

It was Jill who surprised Gaster, a hand on his arm, making him jump violently from where he was reading the latest print out. “Doctor…”

He sighed, adjusting his glasses. “Yes, yes, what is it?”

She frowned, crossing her arms. “You need a break. You’re about to split apart at the seams.”

“Oh? And what would you do if it-”

“If it was my child,” she bit out at him, “I wouldn’t let them wake up to a parent on the verge of a breakdown.” She took in a breath, sighing. “It would make them feel guilty, Gaster. And you don’t want to do that to him.”

Gaster grit his teeth, looking down at the little skeleton in the bed. Still no movement, no sign of increased health…he sighed, dragging a hand down his face. “Perhaps…you’re right.”

Jill’s frown melted into a soft smile, reaching out for his shoulder. “He loves you, and it would tear him up if he thought you were sad over him. Go on, go and get out for a night, we’re here in case anything happens.”

Had it been under any other circumstance, or had Gaster been thinking straight, he probably would have ignored her request that he go out. He would’ve sat down, read a book, ‘relaxed’ at his son’s side.

But Jill was right…he…needed some time away. Away from the walls and the beeping machines and his son looking helpless in bed. Just for a bit, he swore, and he’d be right back in an instant. Just for a bit…

———————————————

A large furry paw gripped the teapot, slowly tilting it and letting the steaming tea pour freely into the cup, tilting it back to pour into another. The teapot, a simple white one with a large yellow flower painted on it, was placed down between the cups and a large furry being sat down on the small chair, making it creak. A skeleton sat across from him, and a hand gripped the cup, slowly bringing it up to sip.

“Thank you, your majesty. It has been a while since we’ve had a time for tea.”

“Please,” rumbled out the jolly king, taking his own tea cup in hand (practically encompassing it with his paw), “you can always call me Asgore, Gaster.”

Gaster tilted his head, giving a soft smile. “Asgore. It’s odd calling you that, despite all these years.”

“Indeed.” They sat in silence for a moment, Royal Scientist and King, friend and friend. Asgore let out a sigh, the steam being blown from his cup in that manner. “He is not better then?”

“No,” Gaster muttered, “Not. Not yet, at least. He will be.” 

Asgore stared at him, his eyes slipping down to where Gaster’s hand shook around the tea cup, the other hand laying on the table and he reached over, cupping his hand around the empty one. “He will be. He is your child, and you are nothing if not determined, yes?”

Gaster sighed, his hand tilting a bit to squeeze Asgore’s in return. “I’m glad you have so much assurance in me.”

“Someone has to, Doctor.”

Gaster tried not to snort into his tea, how rude, and he just smiled and shook his head. Here in the garden, it was just the two of them, like old times. Before one became a King and the other delved into science. Before Asgore married…before she..and the children…

He tried not to think about it, going back to look at his tea. “I feel helpless. This isn’t the science I’ve studied. It’s medicine.”

“Which is what others have studied,” Asgore nodded. “And they will be able to help, as best they can.”

“I don’t want the best they can,” Gaster mumbled. “I want them to succeed.”

Asgore had nothing to say to that, except to squeeze his hand again. They sat in the garden, in the sunlight, Asgore staring at Gaster who stared through a window, sipping tea and trying to pretend his world wasn’t falling apart around him.

————————————

A small shudder, a twitch of the hand, and a sigh before his head rolled to the side, nuzzling into the pillow. One of the machines beeped lightly, rising as if in a heartbeat, unbeknownst to the scientists who were busy making calculations on a chalkboard and pacing while holding a thermos of coffee.

**Notes for the Chapter:**

> KingDings is such a soft couple, don't you agree
> 
> Just chilling with tea. Trying to pretend their lives aren't irreversibly changed due to outside forces.
> 
> Someday I'm gonna write a list of all the Disney/Pixar movies and just make AUs from them bc no one can stop me and I feel like that'd be FUN and AWESOME.


	3. Sleep, Sans, Sleep Well

**Summary for the Chapter:**

> Sans is awake, but...will it be for long?

**Notes for the Chapter:**

> Semi short but the gang is getting closer to an answer!!

Sans wouldn’t remember the week he spent half in and out of sleep. He wouldn’t remember his father cradling him, testing him for everything and anything, gently asking him questions over this and that and another. Honestly, he would barely remember being given so many new pajamas to wear while he slept.

The first thing he does remember is being _absolutely starving_ when he got up. He whined, pouting at the loud beeping noise of the monitor, and how his daddy hadn’t gotten him up for oatmeal. He shifted, pulling up the blanket with a sigh before squirming to sit up. Gaster was at the end, asleep in the chair, snoring, his glasses tilted on his face.

He was startled awake by a small hand patting his face, Sans grumpily staring up at him. “I hungee! No sleep, Daddy.” He whined when Gaster swept him up in a hug, limply letting him as he continued to pat at his face grumpily.

With that, things were…still weird.

Sans was left at 1 HP. None of them could figure it out. Gaster seemed the most perplexed as Jill playfully fed Sans the oatmeal, making silly noises with him. “It’s impossible,” he muttered, pacing with the folder. “No monster stays at 1. They either begin to heal or…” he stopped, shaking his head. Blobber bobbed his head, his comical hand holding a notepad.

“Right, right. But we don’t know about past ones,” he pointed out. “It could be something new.”

Roswell scoffed from where he stood near the wall. “New?”

Blobber nodded again, bouncing back and forth, making Sans giggle as he watched, his mouth full of oatmeal. “Like humans, we too adapt to our environment. Humans in the past, for example, would probably huck up with all the preservatives in food nowadays.”

Gaster paused, twirling the folder lightly. “What are you saying?”

Tonk snapped his fingers. “Oh I get it! Like how they used to call it ‘consumption’ back then. Perhaps the 1 HP was labeled under a disease or affliction, something much more rare now due to…modern…science,” he trailed off as they turned and stared at the little boy in the bed, looking so much more tiny than he was. Jill was happily giving him a juice box, and he looked entranced in the bendy straw, sucking up the juice quickly and making the box squeeze inwards. He waved at Gaster when he saw him staring.

Right. Modern science.

Gaster let out a sigh. “Let’s look for it then. If anything at least this would be a good way to help anyone else should it occur again.” The others nodded, and off they went to work, letting Gaster tend to his son by cleaning his face and reading him a story.

————————

“Sucwose.”

“Sucrose.”

“…pokey thingy.”

“Pokey thingy.”

Sans poked at his mixture, then started to swirl it, giggling under his breath as he leaned over the bowl. “Mmmm. Vaniwa extwact!”

Cara popped open the bottle, dripping a small drop inside before capping it again. “There ya are.”

“Ooohhh,” Sans mumbled, eye lights round with wonder as he stirred faster. “And nows! Ummmmm wock salt!”

She slid a few shakes of the salt in. “Like that?”

Sans giggled, stirring faster then placing his bowl on the table with a puff of pride. “Ta das!”

Cara clapped politely. The bowl of instant ice cream was…well it was nice but he had added a purple coloring to it and it just…it looked like sticky slime to her. “Good going! It looks great. Ya gonna eat it?”

Sans pushed the bowl closer to her with a shy grin and she melted. Awww. He was letting her have it. How sweet! It still looked funky. “Oh honey…you sure you don’t want a bite?”

Sans giggled. “Maaaaybe a wittle?”

“Deal.”

She dug out some plastic spoons and they tapped their spoons together playfully, giggling as they dug into the ice cream. Huh. Not bad. Not chilly but she didn’t like super cold ice cream anyway. “You’re a good cook, little man.”

Sans giggled, licking his spoon slowly. “Thankee. I wikes ice cweam.”

“Heh, same, kiddaroo.”

They were striking out pretty hard, but one of them had gotten permission to go into some old archives. They had learned that it was true, having 1 HP was nearly unheard of…nearly.

There were a few instances, back before Asgore’s great grandfather, so the others were off dissecting the books and the research behind it while she carried on distracting the very bored little boy.

He yawned, his eye sockets drooping-she wondered how, exactly-and he rubbed at his eye sockets with a whine. She chuckled. “Nap time, kidarooni.”

“Noooo…” he whined, even as she pushed the table away from the bed, picking up the little stuffed monkey one of them had bought for Sans.

“Yuup,” she popped her lips, dragging the blanket up around his shoulders and letting him cuddle the monkey. His pajamas had little jungle animals on them, which matched his new friend. She tucked him in, smiling. “Sleep on, you need it to get big and strong!”

“Mmm, wike Daddy?” 

Cara tried hard not to snort. Gaster? Strong? Man was a toothpick. Tall, sure, but he sure looked like one blow of the wind could swing him into the air. “Yeah, baby, like your daddy. Go on then, sleep.”

Sans hummed, shutting his eye sockets and instantly dozing off. His time between sleep and awake was slowly getting lengthier, but it was nowhere near enough for his age. It was perhaps like an infant, who woke just enough to eat and then nodded off again.

She clicked on a small nightlight in the shape of a hot air balloon before flicking off the lights.

They’d figure this out.

They had to.

**Notes for the Chapter:**

> You ever get sick so bad you just kinda barely remember waking up but you know time has passed bc it's been like 3 days? Funky.


	4. Dress Up With Muffet

**Summary for the Chapter:**

> Sans gets to dress up ALL ON HIS OWN!!!
> 
> Oh and they meet up with Muffet

**Notes for the Chapter:**

> I'm in a discord and our prompt was 'have your MC wear their favorite outfit' and I was like  
> I know the perfect story for this!!!

Today was a very important day!

Today, Sans was meeting someone veeeery important to help him with his low HP…

But beyond that! Today! Daddy was letting him dress how he pleased!!!

It was SUCH a big boy thing to do, he was so excited! He climbed out of his bed at home-Daddy took him home once he quit napping so much-and tucked in the ends like he’d been taught. He had a space blanket, matching his wallpaper and the rug under his feet was nice and fluffy.

Okay! First!

Wait, first, lights on!

He turned it on quickly, the little fake chandelier on the ceiling flicking on and lighting up his room as he shucked off his sleep clothes into the hamper. He had a little desk where he could doodle or write science formulas down when he wanted, a bookcase, his closet, a bucket of toys including a cute bunny he had been given. It had a green bow!!!

He loved that bunny.

No! Concentrate! Daddy said he could pick his clothes out this morning!

He hurried to the closet door, opening it and pulling open a dresser drawer as well.

First, he chose some socks! Wait...no...they were a bit boring. He frowned, then peeled the pairs apart, grinning. One yellow sock with ducks, and one green one with stars on it! Perfect!

He also dragged his light up shoes from the closet, tucking one sock into each shoe to wait to last. 

He heard Daddy’s door open, and his own door was cracked in case the spookies came to get him and he had to call for Daddy. Daddy appeared, yawning as he saw a little toddler bones digging into a dresser. “Need some help?”

“Nuh uuuh!”

“Okay, I’ll make breakfast, be careful.”

Sans giggled as he pulled out a pile of clothes, digging through it eagerly, not responding. He was too enthralled in being a Big Boy right now! No time for answers!

He found his green froggit shirt, but had a hard time choosing between a pair of jeans and shorts...but then he found some pink sparkly pants that Daddy’s friend Muffet had given him as play clothes. Perfect!

He tugged the shirt on, rolling around on the floor as he started pulling on the pants. They were a bit tight but they sparkled and he liked sparkles!

Oh wait. What if it was cold?? 

He jumped in the closet, hands waving at a puffed up jacket he had. He thought he had caught it, but it was a play boa that he’d gotten in a toy set. Hmmm…

With a froggit shirt with short sleeves to his elbows and a white stripe around his belly, sparkling pink pants that were very tight and went to his ankles, and mismatched shocks and his light up sneakers, he dragged the fluffy blue boa around his neck, then wrapped around his arms to keep it on him.

Last but not least, he grabbed a pair of mittens-just in case it was cold-and a beanie with stripes on it. Hmmm. Was that everything? He felt like he was forgetting something. 

Oh well!

He marched downstairs slowly, Daddy would be SO proud of what he’d accomplished!

He hurried into the kitchen, screeching on the tile to a stop and squeaking, “Daddy! I’m weady!”

Gaster took one look and had to look away to prevent from bursting into laughter. Instead, he looked back and smiled at Sans. “You look marvelous, son, but…” Oh. Oh no. The little face had crumpled. No no. “You look absolutely handsome, darling.” He picked Sans up onto his hip, offering him a cup of juice that he took awkwardly in his mittened hands, now looking happy as a clam. 

Gaster sighed, shaking his head with a smile as Sans started to hum, swinging his little legs wrapped in sparkly pants.

This day was going to be interesting…

\----

“A hu hu hu~ You take it to be a poisoning of a sort?”

Sans was _thrilled_ to see Muffet and show off that he was wearing the pants she had given him. Right now he was busy climbing around in her lap, her multiple arms leading him back and forth and making him squeal in glee as she sat at one of the tables in the lab.

Roswell grunted from where he was tilting his seat back, feet on the other table and a sucker stick in his mouth. His hair stuck up from fretting about everything so much and pulling on it. “Seems like it, most we can get to it. That’s what lowers an HP right?”

“Sometimes~” she purred, leading the toddler on one arm and swinging him around much to his glee. One elegant leg crossed over the other, five eyes blinking in sync. “A hu hu hu~ but normally once a poisoning is done, it lets the HP regain. And his has not.”

“Right,” Gaster grunted from his own seat, a hand holding up his head, watching Sans with a concerned eye. “Which is why we wondered if perhaps you knew anything.”

Her head tilted, pigtails bouncing lightly as she hummed, one hand tapping long fingernails against her chin. “There...is something, or was something, that could incapacitate an enemy to the point of an illness-filled life.”

Blobber wobbled in place nervously. “W-Was?”

“My mother had used it in the war, so I assume it has long gone extinct.” She shrugged, swinging Sans onto her shoulders and letting him dig his little fingers into her hair as she laced two hands together, the others making gestures as she spoke. “No hard feelings, dearies, but yes, when she felt quite threatened or feared that she would be found out, she would lace her cave entrance with an essence of this flower.”

Jill twirled her fork in her noodles, her lunch having been interrupted by the sudden meeting. “So how would that help...oooh reverse engineering…” she mumbled as Muffet nodded, one hand touching her own knee now. How one kept up with so many hands, it was hard to tell, Roswell thought as he watched.

“Yessss. I’m not one of science but I assume you could use it, examine it, make perhaps an antidote or a reversal.”

Jill traded a look with Blobber, who seemed to wiggle an affirmative. It seemed to be their only answer for now. Gaster nodded. “Do you happen to recall what it was?”

Muffet hummed, slipping Sans into her lap and cuddling him as he giggled, looking up at her with a smile. She smiled back, fangs glinting in the light, making Roswell shudder. She looked like she could eat the little kid up in a moment.

“Mortis Allano~ A hu hu hu~” Her eyes swung up, and they felt each eye pick a target, frighteningly enough. “Do be careful dearies. As pretty as the flower is, one often overestimates one’s place in the universe, and nature is eager to show you it.”

**Notes for the Chapter:**

> People may think the ads with the kid wearing a diaper on the head and two different shoes is exaggerating but my mom once told my sister to put her shoes on so she chose a left boot to her right foot and a light up shoe on her left foot and decided that that was her favorite combination.
> 
> I mean I was also the kid who slept in their Halloween outfit for a week and cried if even the mention of taking it off came up sO


	5. Flowers and Failures

**Summary for the Chapter:**

> A flower hunt ensues.
> 
> But it's not good.

**Notes for the Chapter:**

> I had an idea. And then it seemed too easy. So now I have another!

Mortis Allano. From the history books, it was...it was a pretty flower. It had purple petals with black edges, the stamen were long and curled on the inside, and no matter where it grew, it always had two exact leaves, one higher than the other. It looked a bit like a bell shape, but up, like a cup. 

According to the book, it could either smell like nothing at all-ensuring whoever touched it was unaware-or it smelled like your most favorite thing in the world, causing one to become curious and traipse themselves deeper into the forest.

Either one could have helped Muffet’s mother-Tuffet-during the war, so they were prepared with masks and ventilators, just in case the smell was _too_ enticing.

Muffet had gleefully taken up the job of caring to Sans, appearing like an older sister than anything else, or so Roswell saw. Sans clung to her like glue, and it seemed Gaster trusted her to watch his son.

(But monsters trusted each other without fail, didn’t they? Or, well, Roswell had never quite seen them give one another a reproving eye, or hesitate to accept or offer help. Now that he thought more on it, they did the same with humans, despite their...rough past.

He took out a cigarette as they headed out. What a weird thought train to have…)

Sans, to his credit, didn’t kick up a fuss and was happy to show Muffet his numerous little projects he’d made while in bed recovering. At least he seemed ecstatic about the whole thing.

But...it was to no avail. 

They headed out in their science RV (Blobber called it the ‘Revver’, and Roswell had no idea what he meant by that) to the last known sighting of said flower, which was far into the forest around Mt. Ebbot. Roswell could recall playing with a few school friends on field trips here, parents cautioning them from running too far and getting lost. Good memories.

Cara flung herself out of the RV and wheezed as she hit the ground. “Sweet Earth! I’ll never take you for granted again!” She bowed down, fake sobbing as Jill wobbled out on her heels with swirls in her eyes. Gaster came from the driver’s seat, crossing his arms.

“Come now, I’m not that horrible a driver.”

“SIR!” Cara yanked her head up with a shriek. “YOU DIDN’T USE YOUR PHYSICAL HANDS TO DRIVE!”

“So?”

Indeed, said magical hands were floating nearby, one holding a clipboard as Roswell unwheeled the awning to keep them from the harsh sun as Jill laughed nervously. “Doctor, there’s a reason people don’t use magic to drive.”

Gaster frowned, turning away from the obvious wheel indentions in the mud where they suddenly off-roaded into the forest. “Pity, seemed easy to me.”

“You weren’t being tossed around like a jumping bean!” Cara finally got up and collapsed in a lawn chair that Roswell had dug out. She winked at him, sticking her tongue out. “Thanks.”

“Ya know, I didn’t pull that out for you,” he grumbled, but headed back in to bring out more all the same. Tonk and Blobber helped take out the science equipment as Jill sighed and pulled one of the many history books from the trunk they carted outside. She dusted it off, taking a seat on it as she flipped through the pages.

“Okay so, it often grows near or around caves-which reasons out why Muffet’s mother would have found its uses first-as the seeds stick to bear fur more easily than any other,” she said as she flipped a page, reading over it easily. “But she’s right, there hasn’t been any sightings of it since the war.”

“Only because no one was looking for it,” Gaster said as his hands helped lower the flasks onto the table as he dug into a small bag, pulling on gloves. “Why look for a weapon when we’re at peace, hm?”

He was right, she supposed, but still couldn’t shake the feeling they were going to come out of this empty handed and downcast.

They took various directions. There were two caves to the north, one that led to an underground portion of the mountain, one near a river, and then, finally, one in the middle of the forest on a hill.

Jill and Cara scouted out the two caves off to the north. Cara found several bats, and Jill found a glowing mossy rock. She sighed, tossing it in her sack. “Well, at least that’s pretty...cool. I guess.”

Tonk went to the one near the river, but reported back that it was all flooded inside. All he had found was a few little guppies swimming in circles. Blobber took the one in the middle of the forest, heading out with Gaster.

They found several flowers, but none matching the one they needed.

Finally...they faced the mountain.

It wouldn’t be out of the question for Muffet’s mother to have used it as a hiding spot. After all, many monsters camped out around the mountain during tense times. The cave was wide, and between a few cracks they could see lines of ivy, little dandelions sprouting between. Cara cracked a glowstick, grinning. “Let’s find this flower.”

Despite the fact that it grew near cave entrances, they knew that there could be instances of it deeper in. So they slowly started to explore. Tonk paused at a large rock, peeking around it as Blobber, kept his head bent down, careful of where he walked. Jill stumbled over a rock, grumbling as Gaster walked ahead, his many hands swinging around and touching the walls and the ground.

Cara found it, deeper in, near a small pond with algae on the side.

It was beautiful. It was small. But it was _there_. 

“Okay, gentle,” She whispered, as they slowly dug a trowel into the dirt around it in order to capture the roots. With Gaster’s hands they managed to plant it back into the pot, and they cheered, quickly picking the pot up and getting out of there. She whistled happily, grinning as she kept the pot close to her chest in an effort not to drop it. “I can’t honestly believe it!”

“Neither can I,” Gaster smiled, sighing as he straightened out his jacket. “But that doesn’t mean anything yet. We have to take samples, start doing tests…”

“We’ll get it when we get back!” Jill shooed them both inside the RV quickly. “Let’s go let’s go!”

And off they went...happy as a clam…

How bittersweet…

~~

“...what do you mean?” Jill asked, staring at Muffet with wide eyes.

They had made it back. Sans was asleep in Muffet’s lap, clearly having shown her the small clay spider he’d made a while back, and two of her arms kept him still as one hand pointed at the flower. All her eyes blinked in that unnerving way Roswell had started to dislike. “You can’t see it, I suppose...but yes. The flower is dead.”

They all turned to it.

It appeared just as jubilant as in the book. Just as crisp, just as fresh and happy looking. And then one of the stamen just...rustled in the cool air of the lab and snapped, tumbling down onto the table.

She blinked again. “It was long dead by the time you’d found it. I wouldn’t blame yourselves. It’s still mightily poisonous, yes, but any properties you could venture to gain would be impossible.”

Gaster sighed, thumping down into a chair as he rubbed a hand over his face. “Of course it would be,” he muttered as Cara patted his shoulder roughly. 

“Dammit,” she muttered. “Well, we won’t let this stop us, doc. We’ll keep working on it, yeah?”

He didn’t say anything, looking contemplative as he stared at the now obviously brittle flower as the others started to agree with her.

“W-We should do more tests! On other things!” Tonk stuttered out as Blobber bobbed his head.

“His magic, u-uh, other magics perhaps! Yes! All the things!”

Cara clapped her hands, looking serious. “We can do this!”

They quickly left the room, leaving the three alone, both out of necessity and to get away from the now awkward, and depressed, energy around them. Muffet sighed, gently lifting the sleeping tot into two of her arms as she stood, stepping over to him. “I am quite sorry,” she murmured, gently rocking the little boy. “It always had to be a fresh flower. In a few years, there might be more-”

“But he won’t have a few years,” Gaster mumbled, his hand on his chin. “No one knows how long it’ll stay away. Or if he’ll just dust one day. Or if he’ll end up being fine. It’s a mystery, one that I wished my son wasn’t a part of.”

Muffet nodded, slowly handing the little boy over to Gaster, who tucked him into his arm and under his chin. She cupped two hands together, the others on her hips. “...there is...possibly...something else.”

“What could it be this time?” He sighed, scrubbing a hand over his face. “I don’t mean to snap, but it just seems like any ideas haven’t quite panned out.”

“I understand.” Her two hands on her hips smoothed down her skirt. “It’s merely an idea, and I know the doctors wouldn’t have thought of it.”

“What?”

“My Purple attacks, they can force one to do things they wouldn’t otherwise do, a hu hu hu~” she covered her mouth with one hand, covering a smile. “...but it’s because I use their magic against them~”

Gaster frowned in thought. Everyone knew how magic worked, in a manner. They knew Purple made you do things, and that Blue was gravity magic, but only those who used it knew the intricacies. For instance, Gaster knew others knew about his hands, but they didn’t know that they were, in essence, another ‘body’ for him. He was able to ‘see’ wherever the hands went. That Gravity magic wasn’t just ‘forcing’ someone to the ground, that it was literally using their mass against them.

So, using a magic against someone to make them move, well...that did make sense. He nodded slowly. “...okay...and what does this mean?”

“Think about it.” She reached out, her fingers gently stroking the back of Sans’ head. “It’s unheard of, or perhaps rare, but if his magic has started to poison against him. If his magic has grown greater than his body can keep up…”

“Then it’s attacking him,” Gaster finished, gently holding the tiny hand curled into his shirt. “But what does that mean?”

“Hmm,” she hummed, taking back her hand with ease. “Normally, I’m the one who has to release my victims, a hu hu hu~ but...his magic can’t be forced against him, if it’s too low.”

Gaster nodded again. “He has to use it up, you mean. But that can be dangerous for such a young child.”

“But doctor, don’t you use some magic for these?” She pointed at a passing hand that had grabbed up the pot with the flower, nudging it from the edge of the table.

Gaster snorted. “Yes but it’s miniscule, nothing to even ponder over.”

“Not for you. But him?” She made a motion at Sans, tilting her head. “He is your son, after all. Perhaps a construct would be an easy, and physical, way of extending his magic.” She paused, one foot tapping lightly. “And something you can measure, I assume. That way, if he gets too low, it what, disappears? Then you’d know.”

Gaster tilted his head, nodding as he sighed and stood up, tucking Sans close. “You’ve given me a lot to think on, Muffet. Thank you. I know Sans enjoys your visits.”

Muffet had a large grin on her face, fangs glinting in the fake light. “I do so enjoy seeing him~” She stood on her tiptoes and placed a small kiss on Sans’ cheek, and Gaster could feel the light brush of her hair against his chin as she leaned away. A small black lipstick mark stained Sans’ skull as she threw a wave behind her, walking away. “Call me any time, a hu hu hu~”

Gaster had a lot to think on...but for now, he carted his sleeping child back to bed. It appeared that said little boy had had a few bites more of sugar than usual, as suggested by the donut powder around his little teeth. Well, he couldn’t fuss too much over it. After all, spoiling him a little wouldn’t hurt things.

Especially considering, if he wasn’t careful, he wouldn’t have long to spoil him...

**Notes for the Chapter:**

> .............I'm not sure how I feel about MuffetxGaster  
> I don't think I'm going to go that way  
> but  
> ....I did like this little tender moment between them
> 
> .......an idea for an alternative fic, for sure. For sure.


	6. Blaster Master

**Summary for the Chapter:**

> Sans makes...something~

**Notes for the Chapter:**

> I have very specific ideas for monsters sometimes that I tend to forget until they slap me in the face lmao

“No no, like this...push...slowly.”

Sans had his tiny hands up, his face screwed up in concentration from where he sat in Gaster’s lap. They were at home since this was a bit of a private moment. Parents often helped ‘lead’ their child’s magic should something happen, but it was a private moment between parent and child as doing so meant the parent was low on magic for a while, leaving them open to being ill or hurt should something happen.

Gaster’s hands held under Sans’ little arms, his legs crossed to keep the toddler steady. They were in the living room on the carpet, albeit Gaster had a bit of regret. His poor poor knees would be so beaten up after this...for now, he focused on Sans, who puffed unhappily. “Nuttin’!” he squeaked, and Gaster chuckled, kissing his head softly.

“Just let it mold, okay? All that excess, try and let it form in front of you.”

Sans pouted, wiggling his fingers. For a moment, it seemed like nothing would happen, and then-

_pop_

With a pop of blue magic, a little tiny dragon skull appeared, the size of Sans’ hand. It sneezed, and Gaster could count the individual fangs inside of the mouth. The skeleton head blinked, yawning before zooming around in place. Sans gasped, giggling as he clapped his hands. “I did it!”

“You did,” Gaster smiled. “Good job. How do you feel?”

Sans shrugged, but Gaster knew that he probably couldn’t quite explain it. Fair. He could feel the thrum of Sans’ magic, how it seemed to roil beneath his own, and now with the tiny dragon construct, it settled like the ocean after a storm. Still violent and uneasy, but calming...slowly.

“Daddy, what is?” Sans cooed at the little dragon, holding his hands open happily and the little skull zoomed over, chittering and digging into his hands. Gaster chuckled, slipping Sans into the crook of his arm as he tried to stand up, using the couch as a handhold.

“That is a little construct we can make. My father used to call them Gaster Blasters, as mine can be...quite big and menacing.”

Sans giggled, seeming entranced with his own little blaster. His eye ridges knit together, and-

_pop_

Now he had exactly three little blasters, swarming around like tiny bees or cats on Sans’ hands. He squealed excitedly and giggled. Gaster blinked, chuckling as he set Sans on his hip, shaking his head. “No more, now. You’ll tire yourself out. You can play, but they musn’t cause a ruckus.”

“Okay, Daddy,” Sans hummed, leaning on him, seemingly tired out. That was only fair. He’d reached in and yanked magic out to create three tiny constructs. At his age, that would force any little tyke to bed early. Right now however, it seemed to calm him, and everything seemed less like a balloon about to burst.

Gaster slowly pulled his magic away, letting Sans’ settle back in his bones, back at an acceptable level.

~~

Roswell popped a piece of crackerjack into his mouth, chewing slowly. “I got a question. What is it?”

Blobber seemed excited to explain as Sans showed an array of little...dragon things off to Jill. “They’re constructs! How intuitive!”

Roswell nodded, passing a piece of the popcorn to Sans who immediately chewed on it, clicking his teeth at the sticky treat. “Right right. ...what’s that?”

Tonk, who was busy nudging said little dragons away from his magazine he was reading, perked up. “I can explain this! Hang on.” He shut the magazine, quickly yanking it away from curious jaws. “So, you see, monsters have magic.”

Roswell nodded. “...yeah???”

“So some monsters can make…” he motioned at the little skulls. “Constructs!”

“Right but, what for?” he asked, getting frustrated with the roundabout way they weren’t answering.

“It depends!” Tonk chirped, easily maneuvering one back towards Sans and Jill. “For instance, if you hadn’t met it, Muffet has a Cupcake construct. Sometimes she uses it for travel, others to defend herself should she need it.” Roswell nodded along, a little less confused now. “Constructs range from defense to offense to cheap babysitters. In Sans’ case, he’s too young for any of that, but as a monster grows, their parents teach them the ins and outs of their magicks.”

Blobber jumped in, almost excitedly. “Yes, they show them how to summon their traditional constructs, how to make their own, and then eventually they can make their own!”

Roswell clicked his tongue, frowning. “Sans is uh, too young for all that, then?”

“Well,” Blobber hummed nervously, bobbing his head. “...yes...it’s...constructs are a great drain on one’s magic. It’s why parents or adults help children out with simple things. It’s too dangerous to even think of letting them run out…”

Jill hummed, trailing a finger over one tiny dragon, who trilled up at her, the head spinning in place. “But Sans is okay.”

“Because,” Tonk continued, “of what happened. Imagine it like every child is a balloon. Some are full of water, and if you let a little out, the shape distorts and you have to fill them again. Sans was an overfilled water balloon, and what he CAN do isn’t enough to release the excess.” He nodded at the little skulls. “This helps. It’s not a cure, but a bandaid.”

Roswell frowned, sitting up from where he had tossed his legs up on the table. “Wait, hold it, not a cure? Then what good is-”

“Because he’ll survive,” Tonk said, still nudging away too curious constructs while Sans dug into Roswell’s crackerjack when he wasn’t paying attention. “It’s a bandaid until his body can deal with it on its own, and then there’s no need for a cure. I suppose it’s a bit like a real bandaid in that instance. You cover the wound, but all it does is keep things fine until the body takes over.”

Blobber nodded, happily touching each little blaster as it zoomed over. Roswell sighed, running a hand through his hair. “I guess. Damn, this is stressful. What happened to the good ol’ days of blowing sh-stuff up?” He took a double-take, Sans staring at him with wide eye pips, crackerjack box in his hand, cheeks puffed up. “Hey!”

“Hiiii,” Sans mumbled, giggling. “I wants ta blow stuffs up!” Roswell made a face as a few flecks of popcorn sprayed out of Sans’ mouth. Ew. 

“Dude, swallow it first,” he sighed, shaking his head as he pulled out another box from his pocket, avoiding Sans’ interested gaze. “Someone go convince Gaster we gotta blow something up.”

Jill made a noise, sticking out her tongue. “You do it, he’s with Cara.”

“Fiiiine, making me do all the work.” He groaned, pulling himself from the break room chair with ease, shaking off a curious blaster and tossing it to Tonk who sputtered as it smacked him in the nose. Roswell left to his colleagues’ laughter, pondering how much another box of crackerjack would be…

~~

Cara clasped her hands in front of her, whining, “Boss come oooon!!! Ya gotta do something!”

Gaster ignored her, peering into a microscope as one hand scribbled away. “Have you seen these microbes-?”

“Forget the microbes!” She groaned, swinging into a spinning stool, her heels clicking against the metal stand. “Your love life is in danger!”

“Only because you believe so,” he muttered but she ignored him, feet up on a table, hands clasped to her chest with a breathy sigh.

“One wayward scientist, pining for the ruler of his kingdom. It’s like a romance novel~ minus the trash. And impending war.” She paused. “And pregnancy. You should get pregnant, add to the drama,” she waved her hand at him, and he raised an eye ridge, staring at her.

“I already have Sans, and besides...why?”

“Drama!” She waved a finger. “Besides that, you really need to get out and date! Everyone needs an adult night.”

Gaster sighed, shaking his head and pinching the bridge of his nose. “Fine. Fine. If I say yes, will it get you to focus?”

“Absolutely!” She spun in the seat, cackling. “Now I can show that little tot the thrills of Disney!”

Gaster squinted at her curiously. “Was this all a ploy to babysit my s-”

“Were you talking about microbes? We should focus, Doc,” she sprung out of the seat, whistling as she headed to the cabinet of slides, and Gaster sighed, shaking his head.

Maybe she was right, a little catching up with the King wouldn’t hurt anything...

**Notes for the Chapter:**

> Sans blew up a paper-mache volcano, that is all
> 
> lol
> 
> Cara doesn't ACTUALLY know if they have a crush, but he does talk about Asgore a lot, so she has to tease him about something!
> 
> And Sans is so smart, but he's still baby UwU
> 
> Unfortunately without Gaster 'guiding' him, he can't really make these little guys on his own (or well, at least. He could make one and it'd be...really really weird...). Yet. When he's older he can, and he probably will! It's an easier way of using up magic and helping him feel less like he's on the edge of passing out constantly
> 
> Also I really need a giant blaster just toting Sans around and Gaster scolding it for bumping into a vase lmao


End file.
